It is known that bicycle transmissions can be operated by shifting mechanisms. Shifting mechanisms are typically designed to pull a cable which actuates transmission shifting element(s). There are different types of bicycle transmissions that can be operated by cable. These transmissions include traditional chain driven transmissions with rear and/or front derailleur's, internal geared hub transmissions, continuously variable transmissions (CVT's) and others.
Representative of the art is U.S. Pat. No. 6,718,844 (2004) to Hanatani which discloses a bicycle shift control device comprises a base member for attachment to the bicycle, a operating member rotatably supported relative to the base member for rotating in first and second directions, a transmission control member rotatably mounted relative to the base member for controlling the pulling and releasing of a transmission control element, a bracket for supporting a transmission control element diverting surface, and an intermediate member coupled for rotation with the transmission control member. The intermediate member rotates around a first axis, and the intermediate member can move in the direction of the first axis between an engagement position, in which the intermediate member engages the bracket, and a disengagement position, in which the intermediate member is disengaged from the bracket. The intermediate member includes a first cam surface for causing movement of the intermediate member in the direction of the first axis toward the disengagement position during rotation of the intermediate member, and the intermediate member includes a positioning surface for preventing the intermediate member from rotating around the first axis when the intermediate member is in the engagement position.
Reference is also made to copending U.S. non-provisional patent application Ser. No. 12/657,461 filed Jan. 20, 2010.
What is needed is a shift mechanism for a planetary gear transmission having a lost motion gear selector. The present invention meets this need.